FM receiver modules SOUND QUALITY / RECEPTION

[0212995500229]

Hello,
I`m starting a new project that will need FM receiver.

I had searched a lot and there are not too many FM modules, that can be controlled via I2C or any other digital method.
And those that I know of are "cellphone grade" and are said to be noisy, bad sound quality, have poor reception.

Oh, and signal strength feedback is needed. (to make it go silent while seeking station or when signal strenght is low).

Im aware that some noise reports can be due to the I2C communication noise users were experiencing, but I cant say I wasn`t there. Anyways communication noise can be rectified, so it would be great if we would have the info if it was the I2C communication noise or something else.

Please tell what modules did you try and how they performed.

How is the RDA5807 ? Has anyone tryed that one out?

I will start with what I know till now and please feel free to add or to correct me if I`m wrong:

TEA5767
High noise, poor reception

FAE480 and YST936 family modules -EDIT ANY FM MODULE THAT USES Sanyo LC72131 ic can be used.

I have seen some use modules srapped from Hi-Fi recievers and I believe that this is the biggest hope for me.
Those modules use PLL Frequency Synthesizers that control the frequency and they are controlled by Sanyo CCB (Computer Control Bus). -Libraries are out there
But to score that one I would need to start looking at used recievers until I found one that has "FAE480" or "YST936" family and buy it, to scrap the module.
However at a time this is the best choice that I can think of.
https://www.youtube.com/watch?v=XAW5kfl038s&t=4s&ab_channel=VSElectro

[Koepel]

You definitely need a modern digital tuner.

I think that the TEF6686 is the only good option at the moment, but I have not tried it.
The TEF6686 from NXP: https://www.nxp.com/part/TEF6686HN
The chip itself costs 7 dollars.

A bad designed PCB board can destroy a radio signal. I don't know a good radio module that I can recommend.

[0212995500229]

Thank you.
I will take a look into TEF...
Why modern, or I would rather ask modern as from last 10 years or moder as from 20 - 25 years ago?

I understand that newer gets me bigger possibility of communication with arduino, less power usage, etc..., but modern products are not what they were used to be... its like sound quality isnt even playing a role anymore at least that is how Im seeing HiFi market in last years -if you dont get the high end, you get the low end... no budget friendly quality devices can be found anymore... at least in my eyes.

EDIT:
That is some good info (TEF) indeed, this is what I had found:
[1PC NXP6686 Car Navigation Radio Module AM/PM Radio Tuner Chip TEF6686 | eBay]

Looks like they are used in car stereos and I will probably find one / or similar.

[Koepel]

You could buy a very cheap DSP FM radio with a digital tuner from AliExpress for 10 dollars to check what this digital tuning world is about

Is the TEF6686 from 2013 ? I didn't know it was that old. From what I read it is way better than the TEA5767 or the RDA5807.

[0212995500229]

Yep it is that old, I think that I will use it.

I could buy a radio, but I have a feeling that I will found only one IC (with erased nubmers) inside that does everything.

[Koepel]

I opened my cheap DSP FM radio:

The chip under the blob is for the display and the RDA5807 is the radio.

My experience with this cheap radio: weak radio stations have a nasty louder noise, average radio stations are good with good audio quality, the radio station has to be really strong to turn on stereo.

[0212995500229]

Thank you very much for this.
I ordered TEF6686 module, but I`m also waiting if anyone in local radioamater group will find usable tuner salvaged from 90s gear, because I would like to compare them.

[0212995500229]

Hey hey,
I had found Sony tuner in old Sony Xplod cd radio. (Sony CDX-S2000)

Sony 353-01.

I can see some posts with arduino on some russian forums.

Pinout:

List of models with that exact mainboard:

Will desolder it from the main board and will try to make it work

TUX032.ZIP (1.7 KB)

I uploaded the library, because it was hosted on some sketchy site to keep it for future users.

Will post results once I get there.

[0212995500229]

Ok, after 2 days of head scratching and 100km drive to buy second radio, because I tought that my tuner is faulty, I had finaly got it to work
It turns out that schematic is incorrect for some reason and I have to modules on the table.
I2c should not be pulled low via 10k resistors and MUTE PIN should be pulled HIGH with 3k resistor, not LOW.

First observations (with my hacked temporary setup... I know, no need to say it, it`s a hackjob), I did the listening thru good Yamaha amp and bookshelf speakers:

Well it works, reception is not the best that I had seen in my life, but it is on the good side... 7/10 I would say.
It sounds specific to late 90s / early 2000s devices I would say, it`s bassy and I like it.
Output is a bit low tho, but nothing a preamp could not fix.

It tunes in fast... and thats about all I can say for now.

Oh, and most imporant thing to me, there is absolutely no i2c noise leaking to the audio side... Who had such problems before will appreciate this alot.

Tommorow I will build something on a perfboard probably with regulated 5v and 8v supplies, connect both channels.

I think that I will stay with this module, because it is good, I dont see a reason to search further, later I will make auto seek, as it has SMETER pin and I will probably also try to control MUTE pin to cut sound there signal is really low.

[0212995500229]

ANOTHER LIST OF SONY RADIOS THAT I KNOW IT HAS THE EXACT MODULE (in case somebody will need it):

[Koepel]

The TEF6686 should outperform it.

I see now in the schematic the resistors to GND. I should have noticed that, sorry.

[0212995500229]

I ordered TEF module and will compare both when it arries. It will take a bit tho as I ordered from China... this module is really hard to get.

But why do you think it should outpreform the Sony?
We have zero specs about Sony IC on paper, but I remember Sony Xplode radios from the era and they were good.

I will check specs of some Sony radios with that tuner, will see if I can find some specs about the tuner.

Im not sure if I can post links to other forums here, but I can tell that on xda forum I had found a post where user had TDA7786 in android headunit and he swapped it for TEF6866 any his words were:
"Hi, final thoughts - the upgrade in my experience was marginally better - not worth it!"

He described his problems with TDA with following words " poor sensitivity, selectivity, multipath issues etc. My JY TDA7768 is terrible, even with an RF amp"

On the other hand I had found plenty of threads with different radios that use TEF and they were satisfied.

[Koepel]

The radio with a used TEF6686 module is developed in my country. I think this is the origin: https://www.pe5pvb.nl/tef6686/
Everyone seems to be happy with it. The radios with a used TEF6686 module on Ebay/AliExpress/Amazon are based on that design.

I have not bought such a radio yet, my living room has concrete walls and most radio stations are 50km away.

[0212995500229]

Update on Sony TUX-032:

I have setup on protoboard:
-regulated 5v and 8v, seperated 8v regulated rail for arduino
-auto seek program that stops the seek when SMETER pin voltage rises
-antenna is still a piece of wire.

I will try to find a map with transmitters in my area.

At night (10pm) i got 26 stations, 20 crystal clear, 3 still listanable and 3 with poor signal.

In the morning (10am) I got around 15 stations, 7 clear.

Only HiFi component tuners get that kind of reception here... cheap transistor radios here get around 10 stations max, maybee 4 that you can actually listen to.

I know that Sony knew their stuff back in the day, and thrusting that fact didn't let me down.

Once I get further I will probably do a writeup with guide, details and test results.

[0212995500229]

I received TEF modules today, will try it out with XDR-GTK to see if it`s worth the hassle, because code makes me nervous just, by looking at it...

Whoever wrote the program really has some serious skills in C++.

Meanwhile I did the boards and program for lcd version for TUX module, because I would also like to make hifi component tuner for the living room, however I dont have RDS.... TUX should support it I believe, but unless I put one car radio back together and use i2c sniffer to figure out the bytes, I cant make this happen...

I did this i2c sniffing thing before and its a PITA, because there is alot of traffic going on in these devices... so will see, I would have to really wish hard to even consider doing it. If TUX will prove itself better, I will consider.

However now I do have functioning LCD version of TUX program, with auto-tune, manual-tune, auto-mute, auto-tune stop based on avg of signal strenght, followed by program that analyzes the quality pin signal and confirms if station is really good, or just active station with nothing broadcasted (just static) or station with some computer signals.... 30 presets and auto-preset-search function.

[0212995500229]

QUICK COMPARISON BETWEEN TEF6686 MODULE FROM EBAY AND SONY TUX-032:

1.)They both do find same list of stations.

2.)Amount of static is similar with both modules, I can hear that TEF tryes to do something with static to make it better, static sounds somehow different.

3.)RDS on TEF finds station name for only one station, while further work would needed to be done to make RDS on TUX work.

4.)TEF has some kind of DSP or EQ... you have some filters that cut highs to make static quieter, I had something similar in my car.
While some might like that, I dont, but take this as my personal opinion.

5.)TUX measures 45mm * 38mm * 12mm, while TEF is 35mm * 21mm * 7mm.
A thing to keep in mind if space is limited, but also keep in mind that TUX has larger pins that are easier to work with.

6.)TUX needs 5v and 8v supply, while TEF needs only 5v and draws less current.

7.)The sound... again this can be only my personal opinion:

TUX is leaned towards the bass -classic sound one would expect from late 90s / early 2000s tech, that also means that it sounds a bit more loose compared to TEF.

TEF sounds more transparent (transparent sound is actually desired among audiophiles and especially producers, because it represents what it actually is). Also it sounds more bright, upfront and clinical.

I will do further listening / testing and update if needed.

Both are good, I can`t tell one what to choose because they are close.
I would say if you are after DSP... or what the TEF has... go for the TEF,
but if you like oldschool sound go for the TUX.

If further listening doesnt bring any big changes, I will probably stick with TUX mainly because I like the sound and the fact that I do have the program done for LCD and motorised scale version of tuner.

Probably FM tech isnt advancing anymore as much as it used to. Ofcourse last two decades bringed some inovations, but FM receiver is still a FM receiver and this I believe is the reason why both modules are so close.

[Koepel]

Thank you!
That is valuable information for everyone searching for information about the modules.